[time-nuts] BG7TBL FA1 frequency analyzer

Thu Sep 5 15:31:51 UTC 2019

Hi

The gotcha with doing ADEV on any of these devices is that they are all to noisy to get the job
done at 1 second on a fairly normal OCXO. You have to get out around into the 10’s or possibly
100’s of seconds range to get past the noise floor of the measuring device. To work out where the
intercept is, you need a full graph of the devices noise floor vs tau done in the “language” of the
measurement you are running. ( = the floor may change depending on the measurement used).

If you indeed want to do a quick and simple measurement that goes into 1 Hz ( or possibly less) 
the answer is to use a mixer based setup. A single mixer setup ( half of a DMTD) will do a much 
better job than a counter based approach. Cost wise it is not very expensive at all …

Bob

> On Sep 5, 2019, at 12:12 AM, Christoph Kopetzky <ck at cksd.de> wrote:
> 
> Hi Bob,
> 
> I fully agree to your explanation. But I primarily want to see in the compare e.g. the ADEV noise floor of the devices
> with TimeLab or the different compared graphs for one OCXO measured with the FA1, TSA3011.
> If I am able to connect TimeLab with my FCA3103 in the future I also want to compare this TIC with the
> FA1 and TSA3011. Also important would be the fact whether the 'cheaper' versions could be used to measure phase
> noise as the TimePod 5330A or the PhaseStation 53100A devices and how 'low' they are going to do the job...
> 
> These facts would be a great help for time-nuts and hobbyists for a buying decision where the measurement  requirements
> are not so high or a compromise to the technical circumstances of the 'measurements' they are doing.
> 
> The modern requirements of good lab equipment are not always the ability to measure as exact as technical possible because
> higher exactness of the measurement needs horrendous extra expenses for little advantages.
> 
> Important requirements are what I think a good price/performance ratio which allows also good technical measuring results without
> the need to spent several thousands of euros/dollars for the equipment. This is no longer impossible I think.
> The power requirement is also a good point of the new lab devices...
> 
> I also wish to have a high level frequency and timing source as my lab standard as a good caesium clock but I think
> a Trimble Thunderbolt disciplining a good rubidium standard as the SRS PRS10 surely does a good job and does not
> consume a lot of power as a HP 5071A caesium source.
> 
> The 'cheap' TIC's as the FA1 and TSA3011 are little boxes which can be connected to the usually available lab computer or tablet
> is a great enhancement because expensive GPIB cables, cards or adapter are no longer needed and the whole equipment will be
> more portable.
> For my point of view these facts are very important and the reallocated space in the lab can can be used for other things :)
> 
> (Sorry for the longer post)
> 
> best regards
> 
> Chris
> ---
> 'Everything should be made as simple as possible, but not simpler.' -- Albert Einstein
> 
> Am 04.09.2019 um 19:09 schrieb Bob kb8tq:
>> Hi
>> 
>> Assuming Mark’s data is at 10 MHz and 1 second then 0.0002 Hz is 20 ppt. That number
>> can be compared directly against data presented for a variety of other devices. By far the
>> best way to do the comparison would be to take data over a range of tau’s and look at the
>> resulting plot. That way you can be reasonably sure that there isn’t something weird going on
>> at one or another tau.
>> 
>> Bob
>> 
>>> On Sep 4, 2019, at 1:07 AM, Christoph Kopetzky <ck at cksd.de> wrote:
>>> 
>>> This would be an interesting compare.
>>> I want to compare the FA1 and the TSA3011 if I am back in office and have both in my hands...
>>> But I really do not want to buy unnecessary tools...  So if someone has done this it would be nice to read about that.
>>> 
>>> Mark, do you have also a TICC?
>>> 
>>> best regards
>>> 
>>> Chris
>>> ---
>>> 'Everything should be made as simple as possible, but not simpler.' -- Albert Einstein
>>> 
>>> Am 03.09.2019 um 21:21 schrieb Jerry Hancock:
>>>> How would this compare to the TAPR TICC Rev D? The one that has the arduino base?  About half the price I see.
>>>> 
>>>> Regards,
>>>> 
>>>> Jerry
>>>> 
>>>> 
>>>>> On Sep 2, 2019, at 5:50 AM, Christoph Kopetzky <ck at cksd.de <mailto:ck at cksd.de>> wrote:
>>>>> 
>>>>> Hi Mark,
>>>>> 
>>>>> interesting post.
>>>>> So is the FA1 compatible with the TimeLab or Stable32 software?
>>>>> And could I do phase noise measurements with it like the TimePod?
>>>>> 
>>>>> 
>>>>> Chris
>>>>> 
>>>>> Am 30.08.2019 um 22:57 schrieb Mark Sims:
>>>>>> (Hopefully this is not a duplicate post...  hotmail has been having issues)
>>>>>> 
>>>>>> The FA1 is a small, USB powered frequency counter.   You supply it with a 10 MHz reference and an input frequency of 1 .. 80 MHz.   It outputs a text string of the measured frequency every second.  They cost around $80 .. $120.
>>>>>> 
>>>>>> Apparently there is a PLL inside... the text string has a "PLL unlock" flag.  There is no info on how it works and I have not opened mine up.
>>>>>> 
>>>>>> I did a simple noise test on one where the input and ref clocks were from a Tbolt.  It looks like the measurement noise is around +/- 0.0002 Hz.
>>>>>> 
>>>>>> Lady Heather can now read it.  Attached is a screen capture of the noise test.
>>>>>> 
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